Diamonds cut outside capital of Angola for free (6)
I believe the answer is:
detach
'free' is the definition.
(thesaurus)
'diamonds cut outside capital of angola' is the wordplay.
'diamonds' becomes 'd' (abbreviation in bridge say).
'cut' becomes 'etch' (I've seen this in other clues**).
'outside' indicates putting letters inside.
'capital of' suggests taking the first letters.
The first letter of 'angola' is 'a'.
'etch' going around 'a' is 'etach'.
'd'+'etach'='DETACH'
'for' is the link.
(Other definitions for detach that I've seen before include "Take away -- the cad (anag)" , "Remove from something else, say a coupon" , "Remove, cut out" , "Separate one part from another" , "Separate from, remove part" .)